EP1252451A1

EP1252451A1 - Device for connecting two tool parts

Info

Publication number: EP1252451A1
Application number: EP01900130A
Authority: EP
Inventors: Konstantin Baxivanelis; Achim Rothenstein
Original assignee: Komet Praezisionswerkzeuge Robert Breuning GmbH
Current assignee: Komet Group GmbH
Priority date: 2000-02-04
Filing date: 2001-01-08
Publication date: 2002-10-30
Anticipated expiration: 2021-01-08
Also published as: US7066693B2; DE10004895A1; MXPA02007494A; CN1396988A; JP4719396B2; DE50113001D1; CA2398694A1; BR0108053A; IL150949A; JP2003521384A; WO2001057410A1; AU2001223728A1; ATE373177T1; IL150949A0; EP1252451B1; US20030138303A1

Abstract

The invention relates to a device for releasably connecting two coaxially aligned tool parts ( 1, 2 ) which can be axially pressed against each other on separating surfaces ( 36, 38 ) that face each other with a clamping device. According to the invention, at least one of the separating surfaces ( 38 ) is divided into several axially rigid and torsionally soft bearing segments ( 50 ) which are spaced in a peripheral direction, in order to dampen the torsional oscillations that occur during the work process and reduce noise.

Description

Device for coupling two tool parts

description

The invention relates to a device for the releasable coupling of two coaxially aligned tool parts which can be axially pressed against one another at mutually facing separating surfaces by means of a clamping device.

The device according to the invention is intended both for the releasable coupling of tools with a machine spindle (interface) and for the connection of tool parts to one another (separation point). “Tool parts” are to be understood in particular as boring bars, extensions and reducers, adjusting heads, spindle attachment flanges and machine spindles.

When using drilling tools with indexable inserts, an unacceptable noise emission often occurs. This particularly affects tool parts with flat surface bracing. The noise is generated by vibration excitation of the multi-body system "tool chuck machine" due to dynamic cutting forces. The multibody system is stimulated in a broadband manner by periodic or pulse-like processing forces. This excitation spectrum resulting from chip formation causes the tool to swing up. Above all, self-excited torsional and bending vibrations occur. This leads to micro-movements in the joint gap between the tool parts and thus to an alternate opening and breaking of the tool parts after the stick-slip effect (stick-slip effect) and thus to undesirable structure-borne noise emissions in the high-frequency range. It should be taken into account that the noise generated during the machining process is accompanied by micro-movements, which can lead to undesirable chatter marks in the workpiece. To avoid this disadvantage, has already been Proposed (DE-A 4400425) that the tool parts are axially separated from one another at their parting surfaces with intermediate clamps of an elastomeric material bridge and can be rotated relative to one another to a limited extent with elastic deformation of the material bridge. A major disadvantage of this construction is that the material bridge is axially deformable, so that the machining accuracy that can be achieved leaves something to be desired. In addition, the material bridge enables radial deflection of the tool, which can lead to intolerable machining errors, especially with long tools.

Proceeding from this, the object of the invention is to develop a coupling device of the type specified at the outset which leads to vibration damping and thus to a reduction in noise emissions during the working process and at the same time ensures high machining accuracy.

To achieve this object, the combinations of features specified in claims 1 and 13 are proposed. Advantageous refinements and developments of the invention result from the dependent claims.

The solution according to the invention is based on the idea that in addition to a torsionally soft connection of the tool parts in the area of the coupling device, an additional axial stiffening is provided. This is the only way to meet the high demands placed on machining accuracy. In order to achieve this, it is proposed according to a first alternative solution that at least one of the parting surfaces of the clamped tool parts is divided into a plurality of axially stiff and torsionally soft support segments which are spaced apart in the circumferential direction. A preferred embodiment of the invention provides that at least one of the tool parts has a plurality of grooves which are spaced apart from one another in the circumferential direction and are axially open to the relevant separating surface and run essentially radially, the separating walls of which are limited by their flanks and form the support segments. The separating surfaces can be subdivided into a plurality of circumferential parts, of which two circumferential parts, which are preferably diametrically opposite one another, are divided into support segments, while the other, closed circumferential parts are set back axially with respect to the support segments. This measure ensures that no noise can occur in the area of the closed peripheral parts, which have no bending ability and are therefore not torsionally soft. The grooves between the support segments can be filled with a deformable, preferably elastomeric material.

A further advantageous embodiment of the invention provides that the grooves are made with a constant width in the radial direction, so that the partition walls have a radially decreasing wall thickness from the outside inwards. The partitions are designed as bending beams which are integrally connected to the tool part in question at their base point. In order to obtain a connection that is soft in the circumferential direction even with relatively thick partition walls, the wall thickness of the partition walls is preferably weakened in the region of their base point.

The parting surfaces which can be braced against one another are expediently designed to be plane-parallel or complementary conical.

The invention can be used to advantage if one of the tool parts has a cylindrical or tapered fitting pin and an annular surface surrounding the fitting pin, forming the separating surface, and if a cylindrical fitting hole for mounting on the other tool part has took the fitting pin and a fitting hole surrounding the edge, the other separating surface forming end face is provided. The axially rigid and torsionally soft support segments are expediently arranged on the tool part having the fitting bore, the radial grooves being open axially to the end face and radially outwards and towards the fitting bore. In such a coupling device, a clamping bolt is advantageously provided, which is arranged displaceably in a transverse bore of the fitting pin and has an inner or outer cone at its ends. Furthermore, there are two diametrically opposite one another with respect to the fitting bore, which has an inner or outer cone pointing towards the inside of the fitting bore and, during the clamping process with mutual pressing of the tool parts in the region of the separating surfaces, can be clamped in a wedge-like manner with the clamping bolt. With this construction, it is advantageous if the parting surface of the tool part having the fitting bore is divided into the support segments outside the peripheral parts containing the clamping members and is closed in the peripheral parts containing the clamping members and axially set back relative to the supporting segments.

A further advantageous or alternative embodiment of the invention provides that the tool parts can be pressed against one another at their parting surfaces with intermediate clamps of an annular, axially rigid and torsionally soft material bridge.

The material bridge is expediently closed on one end face and divided on its other end face into a plurality of axially rigid and torsionally soft support segments that are spaced apart in the circumferential direction. In principle, it is possible to connect the axial webs to one another by means of a preferably elastomeric binder. As an alternative to this, the material bridge can be provided with two closed ring parts delimiting the respective end faces, which are connected to one another axially stiffly and torsionally softly by a plurality of radially continuous axial webs spaced apart from one another in the circumferential direction. The web spaces can form, for example, a rectangular, trapezoidal, circular or oval cross-sectional opening. A further embodiment variant provides that the material bridge is divided on its two end faces into a plurality of axially rigid and torsionally soft support segments, which are spaced apart from one another in the circumferential direction and meander or zigzag from the two end faces. The material bridge can also consist of a plurality of radially continuous axially rigid webs spaced apart from one another in the circumferential direction, which are connected to one another in a torsionally soft manner by a preferably more elastomeric binder.

According to an advantageous embodiment of the invention, the material bridge is integrally connected to one of the tool parts in the area of the separating surface.

The invention is explained in more detail below on the basis of some exemplary embodiments shown schematically in the drawing. Show it

1a shows a diagrammatic representation of two coupled tool parts in the form of a drilling tool with adapter piece;

Fig. 1b is a side view of the drilling tool according to Fig. 1b without

Coupler;

2a to 2d adapter pieces with differently designed damping parts in a diagrammatic representation; 3 shows a material bridge designed as an attenuator in a diagrammatic representation;

4a to 4f are sectional views through a vibration-damping material bridge corresponding to FIG. 3 with six differently designed damping parts.

The drilling tool shown in FIGS. 1a and 1b essentially consists of a shaft 10, a drill bit 12 arranged on the end face of the shaft 10 and a coupling member 14 of a coupling device 16 arranged on the end of the shaft 10 opposite the drill bit 12.

In the exemplary embodiment shown, the drill bit 12 has two hexagonal indexable inserts 20, 20 'arranged at different radial distances from the shaft axis, the effective cutting edges 22 of which partially overlap radially in their working areas. The indexable inserts are arranged in recesses in an axially parallel flank of a chip channel 24 which opens into a flute 26 of the shaft 10 at its rear end. The coupling device 16 essentially consists of the fitting pin 30 projecting axially at the rear end of the drilling tool 1, a connecting sleeve 34 axially projecting from an adapter piece 2 or a machine spindle and having a fitting bore 32 and a tensioning mechanism for pulling the fitting pin 30 into the fitting bore 32 of the connecting sleeve 34 and for generating a flat surface tension between the annular connecting surface 36 surrounding the fitting pin 30 of the boring tool 1 and an annular separating surface 38 of the adapter piece 2. The tensioning mechanism exists in the ABS couplings shown in the drawing (ABS = registered trademark of the Komet company ) from a in a cross hole of the fitting pin 30 displaceably arranged clamping bolts 40 and two holding screws, not shown, which are guided in internal threads 42, 44 of the connecting sleeve 34 and are diametrically opposite one another. The clamping bolt 40 engages with its outer cone in an inner cone of the adjacent retaining screw and has at its end opposite the outer cone an inner cone for receiving an outer cone formed on the other retaining screw. To establish the connection between the two tool parts 1, 2, one of the retaining screws is rotated against the other retaining screw by clamping the clamping bolt 40. The clamping forces introduced are converted via the conical contact surfaces due to an existing axial offset into a movement which pulls the fitting pin 30 into the fitting bore 32. When the relevant retaining screw is tightened further, there is a flat surface tension between the separating surfaces 36 and 38 and thus a connection of the drilling tool 1 to the adapter piece 2. If the adapter piece 2 is now rotated via a machine spindle to carry out a drilling process, the indexable inserts 20, 20 'penetrate into the workpiece to produce the bore. This leads to torsional vibrations in the drilling tool 1, which in the event of a relative movement in the area of the separating surface can lead to a stick-slip effect and to the formation of high-pitched noises.

In order to reduce the formation of noise, damping measures are taken in the exemplary embodiments shown to produce a torsionally soft connection of the drilling tool 1 to the machine spindle 2. 1 and 2, the separating surface 38 of the connecting sleeve 34 is divided into a plurality of axially rigid and torsionally soft support segments 50 which are spaced apart in the circumferential direction. For this purpose, a plurality of grooves 52, which are spaced apart from one another in the circumferential direction and are axially open toward the separating surface 18, are arranged in the connecting sleeve 34, the grooves 52 of which grooves their flanks 54 delimited partition walls 56 form the support segments 50 on their free end faces. The separating surface 38 is divided into four peripheral portions 58, 60, of which the two diametrically opposite peripheral portions 58 are divided into the support segments 50, while the other peripheral portions 60 are closed and their end face 62 is axially set back with respect to the support segments 50. The partition walls 56 between the grooves are designed as bending beams which are integrally connected at their base point 64 to the connecting sleeve 34 and have a wall thickness which decreases radially from the outside inwards (cf. FIGS. 2a to 2d). To optimize the vibration damping, the width and depth of the grooves 52, the wall thickness of the partition walls 56 and the geometric configuration of the groove base 66 and the base 64 of the partition walls 56 can be varied (FIGS. 2a to 2d). In the case of FIG. 2d, the base point 64 of the partition walls 56 is weakened. In order to protect the grooves 52 against dirt, they can be filled with an elastomeric material. With this measure, the vibration behavior can also be influenced.

The exemplary embodiments shown in FIGS. 1 and 2 have the advantage that they are compatible with standard tools without damping mechanisms and can therefore simply be exchanged for them.

The exemplary embodiment shown in FIG. 3 shows an annular material bridge 70 which can be inserted between the separating surfaces 36, 38 of the tool parts 1, 2 and can be clamped between them during the clamping process. The material bridge 70 is axially stiff and torsionally soft in the circumferential direction. For this purpose, it is closed on one end face 72 and on its other end face it is divided into a plurality of axially rigid and torsionally soft support segments 50 "which are spaced apart from one another in the circumferential direction. In the embodiment shown in FIGS. 3 and 4a, the support segments are separated by the End faces of the partition walls de 56 'formed, which separate the radial grooves 52'. 4a, the partition walls 56 are shown in the unloaded state. When a torsional force acts in the circumferential direction, the partition walls 56 with their support segments 50 are elastically deformed in the manner shown on the right in FIG. 4a. This deformation prevents a stick-slip effect in the area of the contact surfaces and thus undesirable noise formation.

In the sectional representations 4b to 4f, further geometrical design variants of the material bridge 70 are shown, which likewise meet the conditions of an axially rigid and yet flexible coupling of the tool parts. In the exemplary embodiment according to FIG. 4b, the material bridge 70 has two closed ring parts 76,78 delimiting the end faces 72, 74, which are connected to one another axially stiffly and torsionally softly by a plurality of radially continuous axial webs 80 which are spaced apart in the circumferential direction. The left part of FIG. 4b shows the material bridge with unloaded axial webs 80, while the right-hand illustration of FIG. 4b shows the axial webs under the action of a torsional force. 4b are rectangular in cross section in the case of FIG. 4b, they are round or oval in the exemplary embodiments according to FIGS. 4d and 4e.

In the exemplary embodiments according to FIGS. 4c and 4f, the material bridges on their two end faces 72, 74 are spaced apart from one another in several circumferential directions, meandering from the two end faces (FIG. 4c) or zigzagging (FIG. 4f), and are axially rigid and torsion-soft support segments 50 divided. The left image of FIG. 4c shows the material bridge in the unloaded state, while the right image shows how the material bridge bends under the action of a torsional force. In summary, the following can be stated: The invention relates to a device for the releasable coupling of two coaxially aligned tool parts 1, 2, which can be axially pressed against one another at mutually facing separating surfaces 36, 38 by means of a clamping device. In order to dampen the torsional vibrations occurring during the working process and to reduce noise generation, it is proposed according to the invention that at least one of the separating surfaces 38 is divided into a plurality of axially rigid and torsionally soft support segments 50 which are spaced apart from one another in the circumferential direction.

Claims

claims

1. A device for the releasable coupling of two coaxially aligned tool parts (1, 2) which can be axially pressed against one another on facing parting surfaces (36, 38) by means of a clamping device, characterized in that at least one of the parting surfaces (38) in several, in the circumferential direction axially rigid and torsionally soft support segments (50) which are spaced apart from one another.

2. Device according to claim 1, characterized in that at least one of the tool parts has two circumferentially spaced from each other, to the relevant separating surface (38) axially open, preferably radially extending grooves (50), which are limited by their flanks (54) Partitions (56) form the support segments (50).

3. Apparatus according to claim 1 or 2, characterized in that the separating surface (38) is divided into a plurality of circumferential parts (58, 60), of which at least two circumferential parts (58), preferably diametrically opposite one another, are divided into the support segments (50) while the other peripheral parts (60) are closed and their end faces (62) are set back axially with respect to the support segments (50).

4. Apparatus according to claim 2 or 3, characterized in that the grooves (52) are filled with a vibration-damping, preferably elastomeric material.

5. Device according to one of claims 2 to 4, characterized in that the partition walls (56) have a radially decreasing wall thickness from the outside inwards.

6. Device according to one of claims 2 to 5, characterized in that the partition walls (56) as at their base (54) with the relevant tool part (2) integrally connected bending beam are formed.

7. Device according to one of claims 2 to 6, characterized in that the wall thickness of the partitions (56) is preferably weakened in the region of their base (64).

8. Device according to one of claims 1 to 7, characterized in that the mutually facing separating surfaces (36,38) of the tool parts (1, 2) are plane-parallel or complementary conical.

9. Device according to one of claims 1 to 8, characterized in that one of the tool parts (1) has a cylindrical or conical fitting pin (30) and an annular surrounding the fitting pin, which has a separating surface (36) forming an annular surface, and that the other Tool part (2) has a cylindrical fitting bore (32)

Receiving the fitting pin (30) and an end face surrounding the fitting bore (32) at its edge and forming the other separating surface (38).

10. The device according to claim 9, characterized in that the support segments (50) on which the fitting bore (32) having the tool part (2) are arranged, the radial grooves (52) being open axially to the end face and radially outwards and to the fitting bore ,

11. The device according to claim 9 or 10, characterized by a slidably arranged in a transverse bore of the fitting pin (30), at its ends an inner or outer cone with clamping bolts (40) and two diametrically opposite one another with respect to the fitting bore (32), wedge-like with the clamping bolt in the area of the separating surfaces (36, 38) during the clamping process with mutual pressing of the tool parts (1,2) (40) tensionable, preferably designed as retaining screws tensioning members.

12. The apparatus according to claim 11, characterized in that the separating surface (38) of the fitting bore (32) having the tool part (2) outside the peripheral parts containing the clamping members (60) divided into the support segments (50) and in the peripheral parts containing the clamping members (60) is closed and set back axially with respect to the support segments (50).

13. Device for the releasable coupling of two coaxially aligned tool parts (1, 2) which can be pressed axially against one another on facing parting surfaces (36, 38) by means of a clamping device, characterized in that the tool parts (1, 2) on their parting surfaces (36 , 38) can be pressed against one another with intermediate clamps of an annular, axially rigid, torsionally soft material bridge (70).

14. The apparatus according to claim 13, characterized in that the material bridge (70) is closed on its one end face (72) and on its other end face (74) in several circumferentially spaced, axially rigid and torsionally soft support segments (50 ') is divided.

15. The apparatus according to claim 13, characterized in that the material bridge (70) has two closed ring portions (76, 78) delimiting the end faces (72, 74), which are characterized by a plurality of in

Radially spaced from each other continuous axial webs (80) are axially rigid and torsionally soft.

16. The apparatus according to claim 15, characterized in that the web spaces (82) form a rectangular, trapezoidal, circular or oval cross-sectional opening.

17. The apparatus according to claim 13, characterized in that the material bridge (70) on its two end faces (72,74) in several circumferentially spaced from each other, from both

End faces ago meandering or zigzag interlocking, axially rigid and torsionally soft support segments (50) is divided.

18. The apparatus according to claim 16 or 17, characterized in that the axial webs (80) are interconnected by a preferably elastomeric binder.

19. The apparatus according to claim 13, characterized in that the material bridge (70) has a plurality of radially continuous axially rigid, spaced apart from one another in the circumferential direction

Has axial webs which are connected to one another in a torsionally soft manner by a preferably elastomeric binder.

20. Device according to one of claims 13 to 19, characterized in that the material bridge (70) is integrally connected to one of the tool parts (1, 2) in the region of one of the parting surfaces.

21. Device according to one of claims 1 to 20, characterized in that the tool parts (1, 2) are provided in particular in the region of their parting surfaces with a friction-reducing layer.